Structured surfactant compositions are liquid crystalline compositions that are useful in home care applications such as liquid detergents, laundry detergents, hard surface cleansers, dish wash liquids, and personal care formulations such as shampoos, body wash, hand soap, lotions, creams, conditioners, shaving products, facial washes, baby care formulations, skin treatments. Surfactants in the structured surfactant compositions exist in the form of lamellar phases that are planar and/or in the form of spherulites. Commonly, the surfactant phase is present as spherulites, i.e., lamellar droplets, dispersed in the aqueous phase. Spherulites consist of an onion-like configuration of concentric bi-layers of surfactant molecules, between which is trapped water or electrolyte solution. Exclusively planar lamellar surfactant phases or exclusively spherulite lamellar surfactant phases or the combination of both forms can co-exist in the same composition. Structured surfactant compositions are typically pumpable, non-Newtonian compositions that have the capacity physically to suspend water insoluble particles by virtue of the presence of these lamellar surfactant phases.
Structured surfactant systems based on anionic surfactants, more typically branched (C10-C22)alkyl alkali metal sulfates, such as sodium trideceth sulfate, are known. U.S. Pat. No. 6,150,312 discloses structured surfactant compositions that comprise sodium trideceth sulfate, a fatty acid or fatty acid ester, and a zwitterionic or amphoteric surfactant and provide enhanced freeze thaw stability. U.S. Patent Application Publication No. US2003/0180246 A1 discloses structured surfactant compositions that comprise an anionic surfactant and an alkanolamide. U.S. Patent Application Publication No. US2003/0190302 A1 discloses structured surfactant compositions that comprise an anionic surfactant and a cationic surfactant. U.S. Patent Application Publication No. US200610135627-A1 discloses structured surfactant compositions that comprise an anionic surfactant and an amine oxide.